A- General:
1- Definition:
Cyanosis is a bluish coloration of the integument and mucous membranes that occurs when the capillary blood contains at least 5 g of reduced hemoglobin per 100 ml.
2- Clinic:
Clinically, discreet cyanosis can be difficult to diagnose. It is more visible at the ends and mucous membranes (fingernails and feet, lips, ears, tongue).
It can be intermittent, occurring only effort (cries, in the tiny bottles). On the other hand, the existence and intensity of cyanosis are equal hypoxia, according globular figure: the the anemia decreases, polycythemia increases it.
3- Clinical Implications cyanosis:
* Clubbing: glass nail watch, drumstick fingers.
* Polycythemia consequence of anoxia => hyperviscosity generator thrombosis, particularly stroke.
* Squat or “squatting” especially in tetralogy of Fallot. The child remains readily squatting, sitting on his heels.
* Metabolic acidosis, a result of tissue anoxia, prescribe some alkaline water in the morning.
* Access paroxysmal cyanosis: these are congenital neurological events paroxysmal cyanosis. They are often triggered by the cries, the tears, the efforts.
Suddenly cyanosis increases and it appears hypotonia and a brief loss of consciousness. In other cases, it is a sudden pallor or gray skin, followed by a PC (syncope “blue” and syncope “white”): sudden death possible in Access.
* Neurological complications: stroke = deadly and common complications of cyanosis: arterial or venous thrombosis, for brain abscess (germs transplant outside the pulmonary filter), mycotic aneurysms of infective endocarditis, septic emboli).
B- Tetralogy of Fallot:
1- It combines four elements:
– Two fundamental: CIV and pulmonary stenosis, valvular and / or infundibular and / or supravalvular. In general, there is a wide hypoplasia pulmonary artery tree.
– Two quotas: aorta “riding” on the IV septum (dextroposition) and HVD reaction.
2- Pathophysiology:
This is the prototype of the obstacle cyanotic heart disease associated with abnormal upstream communication: there is a volume overload (by ITC) and VD pressure (due to pulmonary stenosis), resulting in an HVD and a reversal of the shunt, which becomes DG when the VD pressure becomes greater than the LV pressure.
3- Clinic:
– Functional features: they are dominated by the CYANOSIS .
Onset usually DELAYED (different transposition), a few months of life, or even sometimes when walking, sometimes earlier in severe forms (it appears when the shunt is reversed). Variable intensity from one case to another.
– “Squatting”, only visible at the age of walking; Dyspnea, fatigue stress;
– Complications cyanosis: fainting or discomfort anoxic, blue or white, during which the breath may disappear (full pulmonary obstruction) their occurrence requiring prompt surgical intervention and put under beta-blocker in the meantime.
– Breath: usually, holosystolic breath, intense and quivering, CIV 4th EICG. Sometimes it takes a éjectionnel and rough character, and second to third EICG (breath PR bunk).
4- radiological signs:
Usually three characteristic features:
– Apex of the heart up (HVD), with normal heart volume (heart “clog”)
– Very concave arc left means (hypoplasia AP)
– Clear lungs hypovascularisés, spindly branches of the PA.
In 1/3 of cases, aortic arch to right aortic button switches to the right of the esophagus.
5- Evolution – Complications:
* Anoxic Aches ++ especially in forms with infundibular stenosis.
* Neurological disorders: vascular thrombosis, hemiplegia, cerebral abscesses in the advanced forms.
* Hematological complications: thrombosis; hemorrhage (blood dyscrasias disorder); hyperuricemia with gout;
* Infective endocarditis.
6- Treatment:
– Anoxic Malaise: O2 mask;
Avlocardyl * IVD (1 ampoule of 5 mg inject up cédation of discomfort).
– Workaround: Blalock-Taussig (anastomosis between the subclavian artery and branch of the AP on the same side) allows to oxygenate the blood, bypassing the pulmonary obstruction. Indicated when the tolerance is bad in the first months of life, the child is too small to make a complete correction immediately: little present.
– Full Correction in CEC: a patch on CIV + pulmonary valvotomy and / or expansion of the lungs by patch.
Age of complete correction: usually around the age of 6 months to 1 year (sometimes earlier or later depending on the tolerance and the anatomical shape). The long-term prognosis is excellent.
C- Transposition of the great vessels:
Full transposition of the great arteries is a malformation in which the aorta arises from the VD and AP born LV, outstanding cardiac chambers also in their normal position. OD normally receives the desaturated venous blood, which passes in the VD, and in the aorta.
Similarly, OG receives oxygenated blood from the pulmonary veins, which goes into the LV and the PA. There is therefore no cross traffic and two circulations, systemic and pulmonary will operate in parallel completely independent of each other.
For that survival is possible, it is essential that there is bidirectional shunts between the large and the small circulation, through communication between the right and left cavities (VIC, CIA, PCA); the tolerance of the heart is the less bad that these shunts are wider.
The aorta is the anterior vessel and AP posterior vessel; in most cases, the aorta rises before and right PA (right transposition, or D-transposition).
D- Eisenmenger Syndrome:
There is a large PAH “fixed” by “obstructive pulmonary arteriolar disease,” with elevated pulmonary resistance complicating the development of a GD shunt, with inversion of the shunt and the appearance of cyanosis, late in general.
=> Operating Abstention (stage surgery is exceeded).